1. Description of Prior Art
In U.S. Pat. No. 3,771,566 to McMath et al, there is shown a vapor recovery adapter for preventing vapor escape to the atmosphere when a storage tank is being filled while allowing escape of vapor at all other times and permitting air from the atmosphere to be drawn into the tank when liquid is being withdrawn therefrom. While the vapor recovery adapter of the aforesaid McMath et al patent has been capable of handling a plurality of tanks connected thereto, it has required a single common line from the tanks to be connected to the vapor recovery adapter. Thus, the vapor recovery adapter of the aforesaid McMath et al patent has not been capable of mounting on a tank. When utilized with more than one tank, it has required fittings for each of the tanks and then a single connection to the vapor recovery adapter.
In U.S. Pat. No. 3,736,950 to Smallwood, there is shown an anti-contamination vent valve for preventing escape of liquid from a tank being filled into the vent line to prevent contamination of the vent line or other tanks connected to the same vent line. Thus, the anti-contamination vent valve of the aforesaid Smallwood patent prevents liquid from a tank being filled from overflowing into the vent line to contaminate the vent line or other tanks connected thereto while still enabling venting of the tank at all other times and allowing air to be drawn into the tank when liquid is being removed from the tank.
Accordingly, when it has been desired to utilize the anti-contamination vent valve of the aforesaid Smallwood patent with each of a plurality of tanks and to also employ the vapor recovery adapter of the aforesaid McMath et al patent, it has been necessary to have one more manhole and the connected fittings than the number of tanks with which the vapor recovery adapter of the aforesaid McMath et al patent and the anti-contamination vent valve of the aforesaid Smallwood patent are employed. This is because each of the anti-contamination vent valves requires a manhole for its installation and the vapor recovery adapter of the aforesaid McMath et al patent also requires a manhole for its installation.
2. Field of the Invention
The present invention is an improvement of the vapor recovery adapter of the aforesaid McMath et al patent in that it enables the use of the anti-contamination vent valve of the aforesaid Smallwood patent with each of the tanks without requiring a greater number of manholes than the number of tanks. That is, if there are two tanks, then the use of the improved vapor recovery adapter of the present invention results in only two manholes being required even though each tank has one of the anti-contamination vent valves of the aforesaid Smallwood patent.
The present invention accomplishes the foregoing through mounting the vapor recovery adapter directly on one of the tanks and have the anti-contamination vent valve of the aforesaid Smallwood patent supported thereby. At the same time, a vent line connected to each of the other connected tanks, which have only the anti-contamination vent valve of the aforesaid Smallwood patent, can also be connected to the improved vapor recovery adapter of the present invention. Thus, the remainder of the tanks have a manhole only for the anti-contamination vent valve of the aforesaid Smallwood patent. Therefore, the total number of manholes is equal to the number of tanks being vented.
An object of this invention is to provide an improved vapor recovery adapter.
Other objects, uses, and advantages of this invention are apparent upon a reading of this description, which proceeds with reference to the drawings forming part thereof and wherein: